GPS-X Technical Reference

Optimizer 402
The variable SSrep j is the weighted replication sum of squares for target variable j and is
calculated as:
Equation 14.37
Where n is the number of independent variable values for which there are replicates, nr v
is the number of replicates for the vth value of the independent variable, zv
is the mean of
the replicate measurements corresponding to the vth variable, z uy is the uth replicate
measurement corresponding to the vth variable, and f vj is the predicted value of response
variable j corresponding to the vth value of the independent variable.
The variable repdof j is the degrees of freedom for the weighted replication sum of squares
for target variable j. It is defined as:
Equation 14.38
As mentioned earlier, in this chapter, repeat measurements are inserted into GPS-X by
placing measurements very close together in time in the .dat file. See the previous
Lack of Fit Sub-Section, located in this chapter, for details.
The weighted lack of fit sum of squares for the jth target variable, SSlof j, is calculated as:
Equation 14.39
As mentioned in this chapter, the user also can provide the replication sum of squares and
the replication degrees of freedom in the lack of fit sub-section of the Optimizer form. In
order for these values to be used by GPS-X, the replication sum of squares option in the
Lack of Fit sub-section of the Optimizer form must be set to User Supplied.
GPS-X Technical Reference